## F.42. pg_tsparser

`pg_tsparser` is a Postgres Pro extension for text search. This extension modifies the default text parsing strategy for words that include:

- underscores

- numbers and letters separated by the hyphen character

In addition to separate word parts returned by default, `pg_tsparser` also returns the whole word.

### F.42.1. Installation and Setup

`pg_tsparser` is included into the Postgres Pro distribution. To enable `pg_tsparser`, once Postgres Pro is installed, create the `pg_tsparser` extension for each database you are planning to use:

    CREATE EXTENSION pg_tsparser;

Once `pg_tsparser` is enabled, you can create your own text search configuration. In addition to `pg_tsparser`, you can use any available dictionary.

For example, you can create `english_ts` configuration for the English language, as follows:

    CREATE TEXT SEARCH CONFIGURATION english_ts (
        PARSER = tsparser
    );

    COMMENT ON TEXT SEARCH CONFIGURATION english_ts IS 'text search configuration for english language';

    ALTER TEXT SEARCH CONFIGURATION english_ts
        ADD MAPPING FOR email, file, float, host, hword_numpart, int,
        numhword, numword, sfloat, uint, url, url_path, version
        WITH simple;

    ALTER TEXT SEARCH CONFIGURATION english_ts
        ADD MAPPING FOR asciiword, asciihword, hword_asciipart,
        word, hword, hword_part
        WITH english_stem;

### F.42.2. Examples

The following examples illustrate the difference in search results returned by `pg_tsparser` and the default parser:

    SELECT to_tsvector('english', 'pg_trgm') as def_parser,
           to_tsvector('english_ts', 'pg_trgm')  as new_parser;
       def_parser    |         new_parser
    -----------------+-----------------------------
     'pg':1 'trgm':2 | 'pg':2 'pg_trgm':1 'trgm':3
    (1 row)

    SELECT to_tsvector('english', '123-abc') as def_parser,
           to_tsvector('english_ts', '123-abc')  as new_parser;
       def_parser    |         new_parser
    -----------------+-----------------------------
     '123':1 'abc':2 | '123':2 '123-abc':1 'abc':3
    (1 row)

    SELECT to_tsvector('english', 'rel-3.2-A') as def_parser,
           to_tsvector('english_ts', 'rel-3.2-A')  as new_parser;
        def_parser    |          new_parser
    ------------------+-------------------------------
     '-3.2':2 'rel':1 | '3.2':3 'rel':2 'rel-3.2-a':1
    (1 row)

See Also

CREATE TEXT SEARCH CONFIGURATION

ALTER TEXT SEARCH CONFIGURATION

### F.42.3. Authors

Postgres Professional, Moscow, Russia